Coupling for a draft beer system



FIG. 1 is a top plan view of a coupling for a draft beer system, in accordance with my new design;

FIG. 2 is a side elevational view of the coupling for a draft beer system of FIG. 1;

FIG. 3 is a top perspective view of the coupling for a draft beer system of FIG. 1; and,

FIG. 4 is a bottom perspective view of the coupling for a draft beer system of FIG. 1. 

The ornamental design of a coupling for a draft beer system, as shown. 